Where does “東ローマ帝国” come from?

東ローマ帝国 (Japanese) comes from Japanese 東, from Old Japanese 東, from Old Japanese 天, from Proto-Japonic *amay.

東ローマ帝国 (Japanese): the Eastern Roman Empire

Definitions

  1. the Eastern Roman Empire

Ancestry of “東ローマ帝国”, step by step

東ローマ帝国 traces back through two separate lines of ancestry.

via Japanese

StepLanguageWordMeaning
1Japanesethe east; the Orient; an easterly
2Old Japanesethe east; the lands east of the 都
3Old Japanesesky, heavens
4Proto-Japonic*amay

via Japanese ローマ帝国

StepLanguageWordMeaning
1Japaneseローマ帝国
2JapaneseローマRome, Roman
3ItalianRomaRome
4LatinRōmaRome and/or Constantinople (the latter as "Nova Roma")
Every word from Proto-Japonic *amayEvery word from Old Japanese Every word from Old Japanese